Effect of land use / land cover changes on hydrological processes and water availability in the upper Bengawan Solo catchment: parameter assessment and application in hydrological modeling

Impacts of changes in land use / land cover (abbreviated to LULC) on hydrology have become an important issue in the last few decades besides climate change impacts. Changes in LULC will probably affect hydrological processes, such as interception, evapotranspiration and infiltration. Changes in hydrological processes will influence the spatial and temporal water availability and could disturb water demand support, increasing the vulnerability to hydrological disasters and decreasing environmental conditions.

The assessment of effects of LULC changes on hydrological processes requires many observed and estimated parameters. Some parameters related to LULC will probably alter following the LULC changes (e.g. vegetation physical properties, soil hydraulic properties). However, assessment of hydrological process parameters related to LULC is still limited, particularly in Indonesia and other developing tropical countries. In order to contribute to a better understanding of the LULC effects on hydrological processes in tropical regions, this research will investigate the hydrological process parameters related to LULC and apply the results in hydrological modelling. The study area will be Bengawan Solo catchment, located on Java island representing Indonesian densely populated areas with intensive agriculture and rapid residential growth.

Several steps will be carried out : (1) assessing vegetation physical properties for different LULC types in order to achieve a better evapotranspiration and interception estimation, (2) assessing variability in soil hydraulic properties for different LULC types in order to achieve better infiltration estimation, (3) parameterizing and applying results of step 1 and 2 into a hydrological model, (4) use the parameters to predict future hydrological response due to future LULC scenarios (i.e. agricultural and urban expansion, application of soil and water management strategies).